To study the interactions of polycyclic aromatic carcinogens with nucleic acids and certain enzymes involved in DNA synthesis. Attempts will be made to isolate and identify carcinogen-bound adducts of DNA and to study further their metabolism, toxicity, influence on cellular replication, and possible interference with DNA synthesis processes. "In vitro" effects of activated polycyclic aromatic carcinogens on DNA polymerase activity will also be studied.